This invention relates to paillettes, that is to say long thin tubes which are used in artificial ensemination, especially. These tubes are plugged at one end and are then filled by introducing a biological element or substance, such as animal semen, an embryo or even viruses. This produces paillettes which are hermetically sealed at one end and filled with the desired biological element or substance and the other end of the paillette has then to be closed. The paillette will then be ready for use and may be stored in the meantime at very low temperature, for example, in liquid nitrogen.